*EDITED: Subject meant to say early 20th century bronze coins Hi All This might be a dumb question but I just got a beautiful 1900 10 Centimes coin - Its very nice and doesn't appear to have been cleaned (as far as I can see, so scratching at all or evidence) but also it doesn't have the radial luster of say, a nice morgan dollar, etc. However, I don't know if the luster varies between different metals, or countries minting process, etc. The coin has also tones to a brown so maybe that's hiding it? I don't know - Would love some opinion / education -
Yes, that coin should have luster just like any other struck coin. It has 3 things going against it, however: It has been circulated. It has environmental damage. And it has been harshly cleaned in an attempt to remove that environmental damage. All three of those are going to destroy any luster it may have at one time possessed.
I see the term "Harshly Cleaned" here a lot - what does that mean? To me that means Steel wool ALso, how can you tell re: the cleaning? Just the lack of luster?
Harsh is probably to harsh of a word to describe it, but essentially anything that would damage the natural look or otherwise change the surface of the coin is considered harsh cleaning. Basically anything beyond a proper dip is too much.
I use the term "harshly cleaned" whenever the surfaces have been seriously disturbed by the cleaning. That could be hairlines from steel wool, fine hairlines from a jeweler's cloth, or some other method that's stronger than a dip. A dipped coin would just be "cleaned." In this case, it appears that some sort of method was used on the top half of the reverse that left the surfaces rough. This could be some sort of brush, but I don't see hairlines. I'm guessing it was some sort of baking soda or chemical concoction to remove environmental damage - but it left the surfaces devoid of luster. Thus, I call it harshly cleaned.
I agree with your use of the term, I was just speaking in generalities. Harsh cleaning has been the accepted term for some years now, it just seems strong to me since it evokes images of a Brillo pad scrubbing.
There are probably more ways of harshly cleaning a coin than one would care to count. Definitely more than I would care to type ! Using steel wool is just 1 of them. And it needs to be pointed out that while destroying the luster on a coin is often a part of harsh cleaning, even coins that have no luster at all, and haven't had any luster for many years, are often harshly cleaned. As has been already explained by the others, when it comes to cleaning coins the primary difference is between - cleaning and harsh cleaning. Cleaning is fine, there is nothing wrong with it ! Harsh cleaning is bad, no matter what method is used. The reason for this is that cleaning does not harm the coin and harsh cleaning does harm the coin. Harsh cleaning can be mechanical or chemical in nature, or any combination of the two. And when I say chemical, that means a long list of substances. For example using ketchup or Coca-Cola or soap would be harsh cleaning - and yes those things have been used to harshly clean coins. And so has just about every other household substance you can think of. The flip side of the coin is there is a very short list of substances or chemicals that can be used to safely clean coins. They include distilled water, acetone, xylene, pure alcohol (or at least pure as you can get it - in other words rubbing alcohol aint it), and the various coin dips - and that's it, the end of the list. But each and very one of them has to be used correctly to avoid harming the coin. And to answer an implied question of yours Tyler, any coin, every coin, that is struck - no matter how old it is - has luster when it is struck. But that luster can be destroyed by many things, among them wear, harsh cleaning, toning, and environmental damage. Even touching the surface of a coin, with anything, will alter, damage, or destroy the luster to one degree or another.
Is your comment about every coin struck limited to coins produced by the typical reduction process used today, or does it extend to the early hand engraved dies as well? I ask assuming that it would apply to all, but since I’m immersed in a machine shop all day long and have equated at least cartwheel luster to lathes and the reduction process; as incorrect as that may be.
Luster is not a function of how the die was made - it is a function of how the coin was struck. If you want to know more, read this article I wrote: https://www.cointalk.com/threads/luster-a-guide-for-beginners.58435/
Yes, it applies to all struck coins, even the very first ones. Luster is a function of, or if you prefer is created by, the metal flowing when it is struck. So all coins that are struck, even ancients, will have luster the moment after they are struck. And saying the moment after they are struck is an important distinction because luster is so fragile it may not remain on the coin for very long IF the coin is handled incorrectly or roughly. Luster can be destroyed, will all traces of it being removed quite easily and by many different things. But if a coin is handled carefully luster can and will last for millennia. Assuming of course it is not destroyed by toning. This can even be seen on some ancient examples that have obvious luster. Metal flows with all coins that are struck, whether they are struck by the hammer method, screw presses, steam presses, or modern hydraulic presses - metal flows. And if metal flows there is luster. Conversely cast coins have no luster.
